Reinforced Resin-Retained Bridge

ABSTRACT

A resin-retained denture bridge having an improved bonding between a false tooth or teeth of the bridge and a retainer wire of the bridge is provided in the present invention, wherein a coupling recess is formed on a lingual side of the false tooth and a protrusion or an omega-shaped bend is formed on the retainer wire. The protrusion or omega-shaped bend is received in the coupling recess of the false tooth after or prior to a resin being filled in the coupling recess, which is then cured to form a secure engagement, so that the false tooth is bonded to the retainer with the end portions of the retainer wire extending laterally from the false tooth.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a non-provisional of U.S. provisional patentapplications Ser. No. 62/490,171 filed on Apr. 26, 2017, which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related to a reinforced resin-retained bridgefor installing a false tooth or teeth in a patient's mouth having amissing tooth or teeth between two healthy teeth.

BACKGROUND OF THE INVENTION

Maryland bridge is a popular resin-retained bridge (a fixed dentalprosthesis) replacing a missing tooth that relies for its retention on acomposite resin cement. This special bridge is designed for temporaryuse, for example, between the implantation of a dental implant root andthe installation of the abutment (for the two-stage design), normally4-6 months or longer, depending on osteointegration process of thepatient. However, the false tooth retained by the bridge fallsaccidently, for example an occlusion on hard food during the patient'schewing, or even falls due to a gradually weakening bonding between thefalse tooth and the retainer.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide a reinforcedresin-retained bridge having an improved bonding between a false toothor teeth of the bridge and a retainer of the bridge.

Another objective of the present invention is to provide a method ofinstalling a false tooth or teeth in a patient's mouth having a missingtooth or teeth between two healthy teeth.

Preferred embodiments of the present invention include (but not limitedto) those set forth in the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a schematic lingual side view of a false tooth prepared inaccordance with a first preferred embodiment of the present invention.

FIG. 1b is a schematic partial cross-sectional view of the false toothshown in FIG. 1 a.

FIG. 2 is a schematic perspective view of a retainer wire prepared inaccordance with the first preferred embodiment of the present invention.

FIG. 3 is a schematic lingual side view of abutment teeth with retentiongrooves prepared in accordance with the first preferred embodiment ofthe present invention.

FIG. 4a is a schematic lingual side view of a false tooth coupled with aretainer wire prepared in accordance with the first preferred embodimentof the present invention.

FIG. 4b is a schematic vertical partial cross-sectional view of thefalse tooth coupled with the retainer wire shown in FIG. 4 a.

FIG. 4c is a schematic horizontal cross-sectional view of the falsetooth coupled with the retainer wire shown in FIG. 4 a.

FIG. 5 is a schematic lingual side view of a reinforced resin-retainedbridge installed between two abutment teeth in accordance with the firstpreferred embodiment of the present invention.

FIG. 6 is a schematic drawing showing a stainless-steel wire mesh usedin a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A reinforced resin-retained bridge having an improved bonding between afalse tooth or teeth of the bridge and a retainer wire of the bridge isdisclosed in the present invention, which is brought about by providinga coupling recess on a lingual side of the false tooth and forming aprotrusion or an omega-shaped bend on the retainer wire. The protrusionor omega-shaped bend is received in the coupling recess of the falsetooth after or prior to a resin being filled in the coupling recess,which is then cured to form a secure engagement, so that the false toothis bonded to the retainer with the end portions of the retainer wireextending laterally from the false tooth.

EXAMPLE 1 Direct Composite Resin Bridge Clinical Procedures

1. Acrylic tooth selection and preparation

Firstly, the replacement acrylic tooth 10 was chosen according to theshape and mould of the missing tooth. After the acrylic tooth 10 wasselected, a round shaped hole 11 of 2 to 3 mm diameter and about 2 mmdeep was prepared at the lingual side of the tooth in between ½ to ⅓gingivally. A horizontal groove 12 about 1 to 2 mm wide and 2 to 3 mmdeep from a mesial border to a distal border of the tooth and across thehole 11 was prepared, as shown in FIG. 1a and FIG. 1 b.

2. Retainer wire preparation

A size 0.030″ (0.76 mm) retainer wire 20 was chosen, and a smallomega-shaped (1 to 2 mm) bend 21 was prepared at about the middle of thewire 20, so that the retainer wire 20 will fit the hole 11 and thegroove 12 of the acrylic tooth 10, as shown in FIG. 2 and FIG. 4a toFIG. 4 c.

3. Secure the retainer wire

The retainer wire 20 was attached to the lingual side of the acrylictooth 10 with the omega-shaped bend 21 being engaged with the hole 11,and the wire 20 being aligned with the groove 12 of the acrylic tooth.The engagement was secured by applying the tooth shade self-curingacrylic resin 50 inside the hole 11 only, not in the groove.

4. Retention grooves on the abutment teeth

The acrylic tooth 10 with the retainer wire 20 was tried in the mouth todetermine the position of retention grooves 32, 33 on the abutment teeth30, 31. The retainer wire extension was adjusted to a right length. Asshown in FIG. 3, the retention grooves 32, 33 were prepared on theabutment teeth 30, 31 corresponding to the retainer wire extension, sothat portions of the retainer wire 20 extending laterally from theacrylic tooth 10 are able to be accommodated in the retention grooves32, 33.

5. Installing

The abutment teeth 30, 31 were scaled if necessary, and cleaned withpumice and water in a rubber cup. The enamel in the retention grooves32, 33 of the abutment teeth was etched with 37% phosphoric acid,washed, dried and coated with an enamel bonding solution using a smallbrush. The acrylic tooth 10 with its retainer wire 20 was installedbetween the abutment teeth 30, 31 with the portions of the retainer wire20 extending laterally from the acrylic tooth (wings) being accommodatedin the retention grooves 32, 33 of the abutment teeth 30, 31, as shownin FIG. 5. The acrylic tooth 10 with its retainer wire 20 were securedto the abutment teeth 30, 31 by applying a composite resin (not shown inthe drawings) followed by light curing for 20-40 seconds. Occlusion waschecked and make sure that there was no interference in centricocclusion or excursive movements of the mandible.

6. Final Polishing

Final polishing of the prosthesis was carried out using graded burs,strips and discs.

In step 3 of the above procedures, the sequence of engaging the retainerwire to the acrylic tooth and applying the tooth shade self-curingacrylic resin may be altered. In this alternative, the tooth shadeself-curing acrylic resin was injected into the hole first, and then theretainer wire was attached to the lingual side of the acrylic tooth withthe omega-shaped bend being engaged with the hole filled with theacrylic resin.

Another alternative is the retainer wire instead of consisting of asingle core is a stranded wire, or even a mesh band with a greaterflexibility. The omega-shaped bend formed with a single core retainerwire may be avoided, when the stranded wire, or the mesh band is used asthe retainer wire, because the stranded wire or the mesh band are ableto be pushed into the hole of the acrylic tooth with a burnisher rightafter the retainer wire is attached to the lingual side of the acrylictooth.

It is apparent that the time for completing the Clinical Proceduresdescribed above can be saved dramatically, if a set of pre-manufacturedacrylic teeth of different sizes and shades are readily available forselection, wherein the pre-manufactured acrylic tooth contains theembedded retainer wire with wings, as prepared in accordance with steps2 and 3 of the Clinical Procedures or the aforesaid alternatives.

EXAMPLE 2

Clinical Procedures

1) Acrylic Tooth Selection and preparation

Firstly, the acrylic tooth was chosen according to the shade and mold ofthe missing tooth's adjacent teeth. After the acrylic tooth was decided,a round-shaped hole of 2 to 3 mm in diameter and about 2 mm in depth wasprepared to the cingulum areas of the lingual surface. A horizontalgroove was formed from the hole to the mesial and distal surface of theacrylic resin tooth at a depth of about 3 mm in width and 2 mm in depthas shown in FIGS. 1a and 1 b.

2) Retainer Mesh preparation.

A stainless-steel wire mesh of 0.5 mm thickness and 3 mm width as shownin FIG. 6 was used, which is sold with a trademark of Masel®. A lengthof 20 mm of the mesh was prepared, and placed in the horizontal grooveof the acrylic tooth with its center being adapted to the central holeby 1 mm burnisher. Then it was secured by applying the tooth shadeself-curing acrylic resin at the hole area only, not in the groove area.

3) Acrylic tooth with its retainer mesh wings was tried in the mouth tocheck any occlusion interference and the retainer wings shall cover ⅔ ofthe tooth width of the abutment tooth. The retainer mesh shall betrimmed to its suitable size. If there was an interference, a groovewill be placed at the abutment natural teeth. If this procedure wasneeded, the local anesthesia will be administrated and horizontalgrooves were prepared into the lingual surfaces of the abutment teeth.

4) Bonding

The abutment teeth were scaled if necessary, and cleaned with pumice andwater in a rubber cup. The enamel of the abutment teeth was etched with37% phosphoric acid for 5 seconds, washed, dried and then coated with anenamel bonding solution using a small brush. The acrylic tooth with itsretainer mesh wings was installed between the abutment teeth and wassecured by applying the composite resin followed by light curing for 20to 40 seconds. Occlusion was checked and made sure that there was nointerference in centric occlusion or excursive movements of themandible.

5) Final Polishing

Final polishing of the prosthesis was carried out using graded burs,strips and discs.

1. A reinforced resin-retained bridge comprising a false tooth, two orthree false teeth, and a retainer, wherein each of the false teeth isprovided with a coupling recess on a lingual side thereof, and theretainer has two end portions and is provided with one, two or threeengaging means between the two end portions corresponding to thecoupling recess/recesses, wherein the one, two or three engaging meansare fixedly connected to the coupling recesses of the false tooth, twoor three false teeth, respectively, so that said false tooth, two orthree false teeth are bonded to the retainer with the end portions ofthe retainer extending laterally from said false tooth, two or threefalse teeth.
 2. The reinforced resin-retained bridge of claim 1, whereinthe coupling recess is a cavity.
 3. The reinforced resin-retained bridgeof claim 2, wherein the cavity has an opening on the lingual side and anenlarged inner space following the opening.
 4. The reinforcedresin-retained bridge of claim 2, wherein the retainer comprises a metalmesh band or stranded wire, and the engaging means comprises a deformedportion of the metal mesh band or stranded wire pressed into thecoupling recess and a resin filled in the coupling recess and coveringthe metal mesh band or stranded wire which are pressed into the couplingrecess.
 5. The reinforced resin-retained bridge of claim 3, wherein theretainer comprises a single core metal wire, and the engaging meanscomprises a protrusion or an omega-shaped bend formed on the metal wirehaving a shape and a size adapted to be fit in the coupling recess, anda resin filled in the coupling recess and adhering the protrusion or theomega-shaped bend of the metal wire to the false tooth.
 6. Thereinforced resin-retained bridge of claim 4, wherein the false tooth isfurther provided with a groove extending from a mesial border to adistal border and across the coupling recess of the false tooth, and themetal mesh band or stranded wire are accommodated in the groove whilethe deformed portion of the metal mesh band or stranded wire is pressedinto the coupling recess.
 7. The reinforced resin-retained bridge ofclaim 5, wherein the false tooth is further provided with a grooveextending from a mesial border to a distal border and across thecoupling recess of the false tooth, and the metal wire is accommodatedin the groove while the protrusion of the metal wire is fit in thecoupling recess.
 8. The reinforced resin-retained bridge of claim 6further comprising a composite resin covering the metal mesh band orstranded wire accommodated in the groove.
 9. The reinforcedresin-retained bridge of claim 7 further comprising a composite resincovering the metal wire accommodated in the groove.
 10. A method ofinstalling a false tooth, two or three false teeth in a patient's mouthhaving a missing tooth, two or three teeth between two healthy teethcomprising: preparing a reinforced resin-retained bridge as set forth inclaim 1; applying an enamel bonding solution to a lingual side of eachof the two healthy teeth for bonding the end portions of the retainer;inserting the reinforced resin-retained between the two healthy teethwith the end portions of the retainer contacting the enamel bondingsolution applied to the lingual sides of the two healthy teeth; applyinga composite resin to cover the end portions of retainer and at least aportion of the lingual sides of the two healthy teeth, so that noportion of the retain is exposed in the patient's mouth; and curing thecomposite resin.
 11. The method of claim 10 further comprising: forminga groove on the lingual side of each of the two healthy teeth beforesaid enamel bonding solution being applied; wherein said enamel bondingsolution is applied to the grooves formed on the lingual sides of thetwo healthy teeth.